Radiation pattern synthesis of dielectric rod waveguide with many corrugations

The radiation pattern synthesis of dielectric rod waveguides with many corrugations is investigated. The guided waves are related in the form of a 2-port circuit and the radiation field is expressed by superposition of waves from the corrugations, so that the radiation pattern can be calculated in a very short time. This expression can be used in a genetic algorithm (GA) to seek the optimum arrangement of corrugations. Synthesized radiation patterns calculated using the 2-port circuit method compare well with patterns synthesised by the FDTD method. Conical beams and spherical sector beams can be synthesized. In the synthesized pattern, there are no unnecessary large lobes such as the grating lobe from a periodic waveguide. The experimental radiation patterns agree well with the synthesized patterns with small difference.